Most of your text should be preserved because it shows the website's Japanese authorship, and it gives it color :)
But for clarity, a few corrections:

In the USA the popular name is "Numa Numa"
> You know "Dragostea din Tei" or "O-Zone Koi-no-Maiahi" known with the phrase "Mai a hi, Mai a hu", dont'you?
You know "Dragostea din Tei" or "Numa Numa", the song that starts with "Mai-ya-hi, Mai-ya-hoo...", don't you?

2ch is not widely known in U.S.
> Yes. You're most surely right. They closely ressemble to Monar and Mo-lala having been beloved in a gigantic BBS website 2-channel.
These characters are duplicates of Monar and Moraler, the famous ASCII art characters on the Japanese mega-BBS 2channel.
( link to http://en.wikipedia.org/wiki/2ch )

Monar is not "public domain", as you state in the FAQ. He is more like "community property", as his character was designed by 2ch all together.
> Many of 2-channellers found it good to achieve to be used as a main character in AVEX products, some found not as a profit making company uses character from public domain.
Many 2channelers thought it was an achievement to be used as the main characters in AVEX products. Some thought it was bad that a for-profit company was using their original characters.